This invention relates to multilink point-to-point protocol (PPP) network access servers (NASs) that allocate ports or channels to users on demand. More particularly, the invention concerns allocation of limited channels among various users including earlier users who already may have been allocated primary channels and so-called back-channels, e.g. so-called 2nd B channels, and later users who may simply desire access to an Internet service provider (ISP) via a port or channel invoked by a dial-up access request.
Ports on a multilink PPP NAS provide a direct connection between a user and an ISP. Thus, an allocated channel may be thought of as being dedicated to a particular user for the duration of that user's use of the channel. Typically, a NAS allocates a primary channel to each user who requests access. It is common practice for a NAS also to allocate a secondary channel, or what may be referred to herein as an auxiliary or back channel, to any user who requests another channel for purposes of increasing download bandwidth. If all available channels on a given NAS are allocated among various users, then no new users can obtain access because there is no available channel. Thus, during busy times, many would-be users will be denied access to their desired ISP by the NAS.
A user who requests a secondary channel may use the channel, and may benefit from the increased download bandwidth, only for a short period of time compared to the amount of connect time, i.e. the duration of the session. Accordingly, once-allocated secondary channels might represent an unused resource. Nevertheless, the channel once allocated is unavailable to other users, users who are denied access by the NAS to their desired ISP.
Heretofore, there has been no deliberate allocation among earlier users of secondary channels and later would-be users of primary channels that intelligently manages contention between earlier and later users of the limited channel resources.